Thousands of people gathered in more than 100 U.S. communities Thursday in remembrance of Michael Brown, the unarmed black teenager whom police shot to death last weekend in Ferguson, Missouri.

The centerpiece of the observations — being held at such historic places as New York's Union Square, Boston Common and St. Louis' Gateway Arch — was a simultaneous national moment of silence at 7:20 p.m. ET.

"I have two grandchildren, and I want them to be able to walk the streets safely without the police shooting them," said Debbie Ray, who attended the rally in St. Louis, of which Ferguson is a suburb.

"There doesn't seem any reason in the U.S. for rifles to be aimed at people in the streets," Ray told NBC News. "Will they have firehoses and dogs in the street next?"

"We want to stand in an effort of love and support and organize community support for how we can mobilize our anger and our upset and our disappointment," said Renee Chapman, an organizer of the vigil at Marshall Park in Charlotte, North Carolina.

In many cities, local organizers broadened the scope of the rallies to remember other victims of what they called "police brutality." People in Kansas City, Missouri, for example, were encouraged to bring posters bearing the names of other people killed by police over the past two decades — a focus that concerned Mayor Sly James, who said: "To start talking about police brutality in a general raw way is simply to incite more problems. It's not a problem solver."

National organizers, who rallied communities from coast to coast under the Twitter hashtag #NMOS14, were adamant that the gatherings weren't protests or boycotts after four days of unrest and confrontation in Ferguson.

"We are not protesting. We are not going to be chanting or anything of that nature," Chantelle Batiste, an organizer of the vigil at New Orleans' 225-year-old Lafayette Square, told NBC station WDSU. "We want to make sure everyone comes like-minded and everyone stays peaceful."